Remotely controlled unmanned submersible vehicle

ABSTRACT

A remotely controlled submersible vehicle having a rigid truss framework suspended from a flotation sphere, three horizontally disposed members of the truss framework being arranged to form a triangular assembly about a vertically oriented center post affixed to the sphere. Thrusters affixed to the corners of the triangular assembly provide for translational and rotational control of the vehicle.

Mime Keatin e [451 Jan 18, 1972 [54] REMUTELY @UNTRULLM) lUNMANNED SUMMERSKBLE VEWULIE [72] inventor: Gerald R. ifieatinge, Bayville, NY.

[73] Assignee: Sperry Rand Corporation [22] Filed: Feb. 9, 11970 21 Appl. No.: 9,759

[52] U.S.4Cl. ..]l14/16R,61/69R [51] lint. Cl ..1B63g 8/011 [58] lFieidoiSearch ..114/16 R, l6E;61/69R [56] References Cited UNITED STATES PATENTS Wiggins ..61/69 R 2,981,073 4/1961 Robinson ..6l/69R 3,475,915 11/1969 Caplan ..61/69R Primary Examiner-Trygve M. Blix Attorney-S. C. Yeaton 57 ABSTRACT A remotely controlled submersible vehicle having a rigid truss framework suspended from a flotation sphere, three horizontally disposed members of the truss framework being arranged to form a triangular assembly about a vertically oriented center post affixed to the sphere. Thrusters affixed to the corners of the triangular assembly provide for translational and rotational control of the vehicle.

9 Claims, 2 Drawing Figures REMOTIEILY CONTROLLED lUNIl/IANNIED SUBMERSIELIE VEHICLE BACKGROUND OF THE INVENTION The present invention relates to a remotely controlled selfpropelled submersible vehicle.

The rapidly developing field of oceanography and the increasing interest in performing various functions in the undersea environment have created a need for different types of submersibles. I-lleretofore most of the developmental effort has centered on manned vehicles but more recently unmanned vehicles have also received attention principally because of the limited capabilities of a human operator beneath the sea for performing underwater search, inspection and work tasks including, for example, checking an electric cable, recovering an object or turning a valve on a pipeline.

Previously developed unmanned submersibles have included both free moving towed vehicles and self-propelled remotely controlled vessels. The present invention relates to the latter category and has the advantages with reference to similar prior vehicles of significantly reduced complexity and substantially smaller size and weight. All of these features are particularly significant from the viewpoint of lowering operating costs inasmuch as they simplify servicing, facilitate transportation of the vehicle and reduce the required load capacity of cooperative surface handling equipment. In addition to the foregoing advantages, the propulsion system of the vehicle is simplified by the provision of a thruster arrangement which is uniquely compatible with the triangular configuration of the truss framework for providing both omnidirectional horizontal translation of the vehicle and rotation about its center axis as well as heave (up-down) and pitch and roll control, if desired.

SUMMARY OF THE INVENTION A submersible vehicle constructed in accordance with the principles of the present invention comprises a pipelike truss framework suspended from a flotation sphere. The truss framework essentially includes a center post, which extends vertically downward from the bottom of the flotation sphere, and three horizontally disposed pipe members arranged in a triangle about the center post and connected thereto by additional pipes extending from the corners of the triangular as sembly to the center of the vehicle. The pipelike construction reduces the vehicle weight and readily permits internal flooding of the truss members to provide pressure equalization at any depth. Moreover, the open framework facilitates servicing of the various components attached thereto for controlling and propelling the vehicle and has the further advantage of flexibility for adding or exchanging instrumentation in conformance with the function to be preformed. Guy lines connected from the top of the flotation sphere to each corner of the triangular assembly aid the coupling at the junction between the flotation sphere and the center post of the truss framework to increase the rigidity and structural integrity of the composite vehicle structure.

Hydraulically actuated propellers are mounted at each corner of the triangular assembly to provide motion control in up to six degrees of freedom, as previously mentioned, depending on the relative magnitude and direction of the thrust generated by the respective propellers the six degrees of control being readily achieved by virtue of the triangular configuration of the truss framework. In operation, power is supplied to the vehicle and commands transmitted thereto for propelling it and directing it to perform assigned tasks through a tether cable connected from the vehicle to a manned surface or subsurface vessel or control station.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a submersible vehicle con structed in accordance with the principles of the present in vention. and

FIG. 2 is an exploded view illustrating the thruster attachment to the truss framework ofthe vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. II, the submersible vehicle 10 comprises a truss framework 11 including a center post assembly l2 extending from the bottom of flotation sphere 13. The truss framework also includes three horizontally disposed pipes l4, I4 and 14" arranged in a triangular configuration about the center post and affixed at their ends to the plates 160, b, c, of thruster assemblies 1170, b, c, respectively. Pipes 18a, 0, b, b, c, c connect from the plates 16a, 11, c to the center post extending upwardly and downwardly as indicated relative to the horizontal plane formed by the triangular pipe configuration I4, 14V, 14". Symmetry of the truss framework relative to the flotation sphere is preferred but is not essential for proper operation of the vehicle. As previously mentioned, all truss members are preferably hollow and open ended to enable water to flow in them for pressure equalization irrespective of vehicle operating depth. This is facilitated by holes 119 formed in the plates 16a, b, c at the point of connection of the truss members thereto as indicated in FIG. 2 with reference to plate 16b.

The flotation sphere is a hollow aluminum shell having a buoyancy, determined by the volume of water it displaces, approximately equal to the total submerged weight of the vehicle members and appurtenant components mounted thereon. Connection of the flotation sphere to the truss framework is provided by means of a pad 21 positioned at the lower extremity of the sphere and having a rod 22 affixed thereto extending down through pipe 12 and secured at the bottom by a washer and nut 23. Straps 24a, b, 0, preferably equiangularly distributed about the sphere, connect between pad 21 and another pad 26 positioned at the top of the sphere. Adjustable takeup clamp 27 (only one shown) on each of the straps enable the sphere to be fastened securely to the truss framework. By this arrangement, in conjunction with guy lines which will be discussed subsequently, it is seen that no holes or welds are required to be made in the sphere other than those attendant to initial fabrication procedures. The hook 28 on the top pad is used for hoisting the vehicle in and out of the water. It will be noted that the tether cable 29 is held in place by a clamp 30 coupled by lines 31 to top pad 26. Clamp 30 is of the selftightening wire mesh type whereby tension in the tether cable is taken up by the clamp so as to avoid extreme tension on the cable connection to motor pump unit 32 and control box 33 which will be described further a little later. In addition, clamping the cable to the top of the sphere in this manner aids in precluding the cable from becoming twisted in the vehicle components. A guard wire (not shown) can be secured around the horizontal periphery of the thrusters for assisting in avoiding fouling of the vehicle on its cable or other obstructions.

The three thruster assemblies are identical and therefore the details of construction will be explained with reference solely to the exploded view of thruster assembly 1717 shown in Fig. 2. Spacers 34 separate plate 16b from L-shaped plate 36b to facilitate waterflow through holes 19, the respective plates being clamped against the spacers as by bolts passing through holes 35. Horizontally directed propeller units 37a, 12, c connect to face 20 of the respective L-plates and vertically directed propeller units 380, b, c connect to face 25 thereof. Guy lines 39a, b and c (not shown) connect at one end through turnbuckles 410, b to angle extension 42a, b on the L- plates and at the other end through cl-evises 43a, b to straps 44a, b located between straps 24a, b, c. Turnbuckles 41a, b are used to tighten up on the guy lines so as to provide coupling between the truss framework Ill and flotation sphere aiding the single point coupling at the top of center post 12. This increases the rigidity and structural integrity of the vehicle. Sleeves 46a, b, c, accommodating legs 4711, b, 0 having spherical feet 4l8a, b, 0 respectively, are afi'rxed near each corner of the truss framework. It will be noted that the height of the legs is adjustable as by bolts 49 passing through aligned holes in the legs and sleeves. If required, the legs can be extended upward rather than downward for the purpose of supporting the vehicle against the bottom surface of an object, for example the hull of a ship. The spherical shape of the feet is preferred in the interest of minimizing the probability of snagging on bottom objects.

In operation of the vehicle, electrical power is supplied to the motor pump unit 32 of a hydraulic control system such as is described in U.S. Pat. application Ser. No. 9,757 filed concurrently herewith in the name of Robert Halsey Pettit and assigned to the assignee of the present invention, the power being supplied through the tether cable which typically connects to a generator on a surface vessel. Control signals for operating the thruster assemblies to propel the vehicle are brought through the cable to control box 33 which is mounted on center post 12 along with the motor pump unit. Hydraulic fluid is supplied to the propeller units for driving the respective propellers in accordance with command signals from the surface station. More specifically, if it is desired to move the vehicle up or down, all three vertically directed propeller units 38a, b, c are activated, the direction of rotation of the propellers being operative to control the direction of vertical motion of the vehicle as is well understood. The propeller of each propeller unit is driven by a fixed displacement hydraulic motor, such as Model Number MF3911- 25 manufactured by Vickers Division, Sperry Rand Corporation, Detroit, Michigan having two flow ports 51, 51 and a case drain port 52 as indicated in connection with propeller unit 37b. Flow of hydraulic fluid in one direction between the two flow ports of a given propeller motor drives the propeller in one direction while flow in the other direction between the two flow ports drives the propeller in the opposite direction. A sump tank 53 is part of the hydraulic system. The interior of this tank has compartments separated by a movable piston 54. One compartment is vented to the ambient environment as by port 55 and the other is connected into the lines of the hydraulic system by way of line 56. The piston is preloaded by a spring 57 forcing it against the hydraulic fluid in the compartment connected to the hydraulic lines so as to raise the pressure in the hydraulic system a predetermined amount above normal atmospheric pressure in air environment. As the vehicle descends to greater depths the increasing pressure of the underwater environment is effective on piston 54 by way of vent 55 to produce a corresponding increase in the internal pressure of the hydraulic system thereby holding it above the ambient pressure by an amount equal to that established by the preload on the sump piston.

Selection of the propeller units to receive hydraulic flow and the direction of flow therein is controlled by means of surface transmitted command signals which actuate related bidirectional, proportional control, servo actuator hydraulic valves in control box 33. It will therefore be appreciated that the vehicle can be maneuvered in several degrees of freedom by appropriate control of the magnitude and direction of the propelling force at the various propeller units. As previously mentioned, unidirectional forces generated at the three vertically oriented propellers provide for vertical propulsion of the vehicle either up or down in accordance with the direction of the generator forces. In a similar manner, by appropriate control of the magnitude and direction of thrusts generated by these propeller units, both roll and pitch motion of the vehicle can be commanded about orthogonal horizontal axes. It should be understood, however, that roll and pitch control is strongly inhibited by virtue of the excellent vertical stability provided by the configuration of the vehicle, that is, its high center of buoyancy and low center of gravity. The horizontally directed propeller units 370, b, c, on the other hand, can be used for translating the vehicle in any direction in a horizontal plane or, alternatively, for rotating the vehicle about its center post as by directing hydraulic fluid into the related propeller pumps in a manner to produce forces directed tangent to a horizontally disposed circle about center post 12. Obviously, the vertical and horizontal propeller units can be utilized to produce any desired combination of thrust vectors for maneuvcring the vehicle. A controller mechanism for operating the propeller units in the foregoing manner is described in US.

Pat. application Ser. No. 9,755 filed concurrently herewith in the name of Gerald R. Keatinge et al. and assigned to the assignee of the present invention. The universality of horizontal control obtained by this thruster arrangement is obtained at the expense of thrust efficiency. In applications where rotational motion is relatively unimportant such as in following an electrical cable or pipeline, one horizontal thruster 37c can be removed or deactivated while the other two thrusters 37a, b can be oriented by means of a wedge 57 inserted between the L-shaped plate and the propeller unit mounting plate 58 of each thruster assembly such that the forces generated by these thrusters are directed normal to truss pipe 14 thereby enabling translational control of the vehicle in the direction of arrow 59 at a higher efiiciency than in the illustrated arrangement.

For the purpose of reducing hydrodynamic drag a fairing can be mounted over a predetermined portion of the vehicle, for instance, over the truss framework. The fairing can also be free flooded in the manner of the truss pipework, to equalize internal and external pressures. In some cases, however, additional drag may be desirable to provide increased damping for easier handling when maneuvering to perform a work task in a close area. In any event, it should now be apparent from the foregoing description that several advantages are realized because of the simple construction utilized in fabricating the vehicle. For example, additional power and control equipment as well as instrumentation such as TV cameras, lighting equipment or manipulator apparatus of the type disclosed in US. Pat. application Ser. No. 9,758 filed concurrently herewith in the name of Robert Halsey Pettit and assigned to the assignee of the present invention can readily be attached to any available part of the framework. Easy accessibility to the equipment also facilitates servicing and, of course, the vehicle can readily be dismantled which in conjunction with its small size and light weight facilitates transportation to work sites.

While the invention has been described in its preferred embodiment, it is to be understood that the words which have been used are words of description rather than limitation and that changes may be made within the purview of the appended claims without departing frorh the true scope and spirit of the invention in its broader aspects.

I claim:

' l. A remote-controlled submersible vehicle comprising a flotation member, and a rigid truss framework suspended from said flotation member including vertically oriented center post means secured at one end to the bottom of said flotation member, three elongated horizontally disposed members arranged to form a triangular assembly about said center post means, and means coupling said horizontally disposed members to said center post means, and

three fixed thruster mechanisms, respective ones thereof being secured to said horizontally disposed members at the respective corners of said triangular assembly in such a manner that the forces generated thereby are tangent to a horizontally disposed circle concentric with said center post means whereby said vehicle may be translated in any horizontal direction or rotated about its center post in accordance with the magnitude and direction of the forces provided by the individual thrusters.

2. The apparatus of claim 1 including three additional fixed thruster mechanisms, respective ones of said additional thruster mechanisms being secured to said horizontally disposed members at the respective comers of said triangular assembly in such a manner that the forces generated thereby are substantially parallel to said center post means whereby the said vehicle may be translated in a direction parallel to said center post means or rotated about orthogonal axes located in a plane normal to said center post means.

3. The apparatus of claim 1 wherein said coupling means comprises a plurality of extended members, two of said extended members being connected between said center post means and each corner of said triangular assembly with one of said two extended members slanting upward and the other downward with respect to said horizontally disposed members.

4. The apparatus of claim 1 wherein said center post means includes a sleeve having a rod extending therethrough, said rod being affixed at one end to said flotation member and having means secured to its other end to hold it within said sleeve.

5. The apparatus of claim 1 including top and bottom pads positioned respectively at the top and bottom of said flotation member, the bottom pad being connected to said center post means,

a plurality of straps connected between said pads and extending around said flotation member thereby securing the latter to said truss framework, and

a plurality of guy lines, at least one guy line being connected from said top pad to a corner of said triangular assembly.

6. The apparatus of claim 1 including three plate assemblies located at the respective corners of said triangular assembly, each plate assembly having a first plate member affixed to the adjacent ends of said horizontally disposed members and said coupling means, and a second plate member spaced from said first plate member and adapted to support respective thruster mechanisms.

7. The apparatus of claim 6 wherein the members of said truss framework are pipelike so that water can flow in them to provide pressure equalization in said members, and said first plate members have holes concentrically located with the ends of said pipeworlc members for enabling water to flow therebetween.

8. The apparatus of claim 7 wherein said flotation member is a sphere and further including top and bottom pads positioned respectively at the top and bottom of said sphere with the bottom pad secured to said center post means,

a plurality of straps equiangularly displaced from one another connected between said pads and extending around said sphere to secure the rigid truss framework thereto, and

individual guy lines connected from each comer of said triangular assembly to said top pad.

9. The apparatus of claim 8 wherein said coupling means comprises a plurality of extended members, two of said extended members being connected between said center post means and each of the individual comers of said triangular assembly,

said center post means comprises a rod atfixed at one end to the flotation sphere and passing through a sleeve with means affixed to its other end to secure said truss framework to said sphere, and further including three vertically disposed sleeve members affixed to said truss framework near the periphery thereof with individual legs having a spherical foot passing through each of said sleeve members for supporting said vehicle on an under or overhead surface. 

1. A remote-controlled submersible vehicle comprising a flotation member, and a rigid truss framework suspended from said flotation member including vertically oriented center post means secured at one end to the bottom of said flotation member, three elongated horizontally disposed members arranged to form a triangular assembly about said center post means, and means coupling said horizontally disposed members to said center post means, and three fixed thruster mechanisms, respective ones thereof being secured to said horizontally disposed members at the respective corners of said triangular assembly in such a manner that the forces generated thereby are tangent to a horizontally disposed circle concentric with said center post means whereby said vehicle may be translated in any horizontal direction or rotated about its center post in accordance with the magnitude and direction of the forces provided by the individual thrusters.
 2. The apparatus of claim 1 including three additional fixed thruster mechanisms, respective ones of said additional thruster mechanisms being secured to said horizontally disposed members at the respective corners of said triangular assembly in such a manner that the forces generated thereby are substantially parallel to said center post means whereby the said vehicle may be translated in a direction parallel to said center post means or rotated about orthogonal axes located in a plane normal to said center post means.
 3. The apparatus of claim 1 wherein said coupling means comprises a plurality of extended members, two of said extended members being connected between said center post means and each corner of said triangular assembly with one of said two extended members slanting upward and the other downward with respect to said horizontally disposed members.
 4. The apparatus of claim 1 wherein said center post means includes a sleeve having a rod extending therethrough, said rod being affixed at one end to said flotation member and having means secured to its other end to hold it within said sleeve.
 5. The apparatus of claim 1 including top and bottom pads positioned respectively at the top and bottom of said flotation member, the bottom pad being connected to said center post means, a plurality of straps connected between said pads and extending around said flotation member thereby securing the latter to said truss framework, and a plurality of guy lines, at least one guy line being connected from said top pad to a corner of said triangular assembly.
 6. The apparatus of claim 1 including three plate assemblies located at the respective corners of said triangular assembly, each plate assembly having a first plate member affixed to the adjacent ends of said horizontally disposed members and said coupling means, and a second plate member spaced from said first plate member and adapted to support respective thruster mechanisms.
 7. The apparatus of claim 6 wherein the members of said truss framework are pipelike so that water can flow in them to provide pressure equalization in said members, and said first plate members have holes concentrically located with the ends of said pipework members for enabling water to flow therebetween.
 8. The apparatus of claim 7 wherein said flotation member is a sphere and further including top and bottom pads positioned respectively at the top and bottom of said sphere with the bottom pad secured to said center post means, a plurality of straps equiangularly displaced from one another connected between said pads and extending around said sphere to secure the rigid truss framework thereto, and individual guy lines connEcted from each corner of said triangular assembly to said top pad.
 9. The apparatus of claim 8 wherein said coupling means comprises a plurality of extended members, two of said extended members being connected between said center post means and each of the individual corners of said triangular assembly, said center post means comprises a rod affixed at one end to the flotation sphere and passing through a sleeve with means affixed to its other end to secure said truss framework to said sphere, and further including three vertically disposed sleeve members affixed to said truss framework near the periphery thereof with individual legs having a spherical foot passing through each of said sleeve members for supporting said vehicle on an under or overhead surface. 